Cancer continues to be a leading cause of death with over 1.6 million new cases of cancer being diagnosed in 2012 and over 500,000 people dying from cancer in the United States alone in 2012. For example, in the United States, breast cancer affects over 250,000 women every year, and represents the most common form of cancer in females. Indeed, it has been found that 1 out of every 8 women in the United States will develop invasive breast cancer during their lifetime and that almost 40,000 women die of breast cancer each year.
Meanwhile, epithelial ovarian cancer is the leading cause of death among gynecologic malignancies in the United States (Auersperg, 2013), with more than 21,000 cases reported and nearly 15,000 deaths in 2011. The standard treatment involves surgical de-bulking, followed by chemotherapy with, for example, carboplatin and paclitaxel. Most patients initially respond to these treatments; however a significant number of patients eventually develop drug resistance resulting in relapse, cancer progression, and death. Furthermore, mortalities associated with ovarian cancer are often due to late diagnosis and/or to acquired platinum-resistant recurrence.
Despite efforts to improve treatment and detection of cancer, cancer survival has still not improved significantly over the past two decades for a number of cancer types due, at least in part, to the numerous subtypes of certain cancers and due to the various mechanisms responsible for the development of those cancer subtypes.
Therefore, novel therapeutic approaches that can target drug-resistant tumor cells are very much in need (Matsuo et al., 2010, Banerjee and Gore, 2009). In addition, elucidating the mechanisms leading to drug resistance should provide basis for development of drugs able to re-establish chemo-sensitivity.